This application claims the benefit of Korean Patent Application No. 1999-44599, filed on Oct. 14, 1999, which is hereby incorporated by reference.
1. Field of the Invention
The present invention relates to a liquid crystal display, and more particularly, to a substrate cleaning technique for a liquid crystal display.
2. Discussion of the Related Art
Generally, a liquid crystal display (LCD) panel is manufactured by carrying out various processes such as a process of forming a thin film transistor (TFT) including an electrode material, a semiconductor layer and an insulating film on a substrate, an assembling of the lower substrate to the upper substrate and an injection and sealing of liquid crystal, etc. In such various fabrication process of the LCD panel, particles such as substrate fragments, and various alien or foreign substances occasionally stick or adhere to the substrate to contaminate the substrate. In order to reduce such a defect caused by the foreign substances, a fabrication process of the LCD panel includes a substrate cleaning process for each step thereof. In connection with each fabrication process requiring cleaning of the substrate, the substrate cleaning is performed in the following: (1) before and after a step of forming a TFT array on the substrate; (2) after a step of forming an orientation film and rubbing the orientation film for forming an orientation of a liquid crystal; (3) after a step of scribing for assembling the upper substrate with the lower substrate and then cutting away each panel from the whole substrate; and (4) after a step of injecting a liquid crystal to the panel and sealing the injected portion.
Such substrate cleaning is carried out by means of a substrate-cleaning module, as shown in FIG. 1. Referring to FIG. 1, the conventional substrate cleaning apparatus includes cleaning brushes 22 for cleaning the upper and lower surfaces of a substrate 20. A pair of cleaning brushes 22 is provided at each of the upper and lower sides in such a manner as to contact the upper and lower surfaces of the substrate 20. As shown in FIG. 1, the cleaning is initiated by passing the substrate 20 between the upper and lower cleaning brushes 22 in the direction of the arrow. Then, the cleaning brushes 22 are rotated at a high speed to remove undesired particles and foreign substances sticking to the upper and lower surfaces of the substrate 20.
In the conventional substrate cleaning apparatus, the cleaning brushes 22 are formed to contact the upper and lower surfaces of the substrate 20 to remove foreign substances sticking to the upper and lower surfaces of the substrate 20. However, the conventional substrate cleaning apparatus cannot remove foreign substances adhering to the side surfaces of the substrate 20. The substrate 20 used in the liquid crystal display panel has a thickness of about 0.7 mm and is susceptible of being contaminated by such foreign substances due to the significant surface area of the side surfaces. Thus, foreign substances generated in various processes during fabrication of the panel become attached to the upper and lower surfaces of the substrate 20 as well as to the side surfaces thereof. Particularly, in the scribing or grinding process, minute particles and fragments of the substrate may adhere to the side surfaces of the substrate 20 to contaminate the substrate 20. This is because in the scribing process, each panel is separated from the large glass substrate by cutting after the formation of the TFT and assembling of the upper substrate to the lower substrate and in the grinding process, the coarse side surfaces of the substrate 20, after being separated, undergo grinding. Such foreign substances sticking to the side surfaces of the substrate 20 cause defects during fabrication of the panel to reduce throughput (yield) and deteriorate the picture quality of the LCD panel.
Accordingly, the present invention is directed to an apparatus and a method for cleaning a substrate that substantially obviates one or more of the problems due to limitations and disadvantages of the related art.
An object of the present invention is to provide a substrate cleaning apparatus and method for a liquid crystal display panel that is capable of removing foreign substances attached to the lower and upper surfaces of a substrate as well as to the side surfaces thereof.
Additional features and advantages of the invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.
To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described, a substrate cleaning apparatus for a liquid crystal display panel according to one aspect of the present invention includes a side-cleaning module arranged at a side surface of the substrate.
In another aspect of the present invention, a method of cleaning a substrate in a liquid crystal display panel includes rotating side cleaning brushes arranged in such a manner as to contact the side surface of the substrate to remove foreign substances sticking to the side surface of the substrate; rotating upper and lower cleaning brushes arranged in such a manner as to contact the upper and lower surfaces of the substrate, respectively, to remove foreign substances sticking to the upper and lower surfaces of the substrate; and jetting cleaning water carrying ultrasonic waves onto the side surface of the substrate at a high pressure to clean the side surface of the substrate.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed.